Perpetual Rotation – The Cycle Attribute

Attributes are a great tool somewhat hidden in the Project Window. We shall use the Cycle Attribute to make a sprocket rotate continually.

When animating, it is not infrequent to have an animation cycle: wheels turning, planets orbiting, etc. This tutorial explains how to make an animation cycle using the Cycle attribute in the Project Window.

We’ll start with a simple scene. A sprocket on a plane, plus a spotlight and a camera.

Here is the base scene file.

We will set keyframes for a 2-second rotation period. We’ll set keyframes with 90º rotation increments (for better control) at 0.5, 1.0, 1.5 and 2.0 seconds and rotate the sprocket 90º in each of them.

But before…

1. Let us set an animation length of 10 seconds in the Project Window (P key).
2. Let us expand the Sprocket object properties and click on the stopwatch icon for the rotation of the Sprocket. This sets the rotation as keyframed, not scripted.

Now, let’s move the time to 0.5 seconds. Rotate the sprocket 90º clockwise.

Repeat, rotating 90º clockwise every time.

If we preview our animation, the sprocket will rotate once, and stop.

We will now add a Cycle Attribute to make the rotation continuous.

Attributes are in the plus menu on the top right corner of the Project Window.

Once we add the Cycle attribute, it defaults to 1 second and 1 cycle.

We need to set it to a 2-second cycle and infinite cycles, as shown in the image below.

That’s it: we are done.

Preview the animation and see the sprocket turn during the whole animation length.

The animation should look like this: